Processing servo data from two or more read transducers co-located on a slider

Abstract

Two or more signals are read from two or more respective tracks of a disk drive recording medium using respective two or more read transducers co-located on a slider. The slider is aligned to the two or more tracks in response to the correlation between the two or more signals.

What is claimed is: 
     
       1. A method comprising:
 reading two or more signals from two or more respective tracks of a disk drive recording medium using respective two or more read transducers co-located on a slider; 
 determining a correlation between the two or more signals, the correlation being based on a difference between the two or more signals over a period of time; and 
 aligning the slider to the two or more tracks in response to the correlation. 
 
     
     
       2. The method of  claim 1 , wherein a relatively high value of the correlation indicates misalignment of the slider relative to the tracks, a relatively low value of the correlation indicating alignment of the slider relative to the tracks. 
     
     
       3. The method of  claim 1 , wherein correlation indicates:
 an amount of misalignment of the two or more readers from the two or more tracks; and 
 a direction of the misalignment. 
 
     
     
       4. The method of  claim 1 , wherein determining the correlation comprises delaying one of the first and second signals to account for a downtrack separation of the first and second read transducers. 
     
     
       5. The method of  claim 1 , wherein the aligning of the slider to the two or more tracks in response to the correlation complements the use of servo marks to detect slider position relative to the two or more tracks. 
     
     
       6. The method of  claim 1 , wherein the two or more signals are obtained from user data. 
     
     
       7. The method of  claim 1 , wherein the correlation is obtained by integrating a difference of the two or more signals over a period of time. 
     
     
       8. The method of  claim 1  wherein the two or more read transducers are separated in a cross track direction by a distance corresponding to a separation of the two or more tracks. 
     
     
       9. An apparatus comprising:
 a circuit that receives two or more signals from two or more respective tracks of a disk drive recording medium using first and second read transducers co-located on a slider; and 
 a controller coupled to the circuit and configured to:
 determine a correlation between the two or more signals, the correlation being based on a difference between the two or more signals over a period of time; and 
 align the slider to the two or more tracks in response to the correlation. 
 
 
     
     
       10. The apparatus of  claim 9 , wherein a relatively high value of the correlation indicates misalignment of the slider relative to the tracks, a relatively low value of the correlation indicating alignment of the slider relative to the tracks. 
     
     
       11. The apparatus of  claim 9 , wherein correlation indicates:
 an amount of misalignment of the two or more readers from the two or more tracks; and 
 a direction of the misalignment. 
 
     
     
       12. The apparatus of  claim 9 , wherein determining the correlation comprises delaying one of the first and second signals to account for a downtrack separation of the first and second read transducers. 
     
     
       13. The apparatus of  claim 9 , wherein the aligning of the slider to the two or more tracks based on the correlation complements the use of servo marks to detect slider position relative to the two or more tracks. 
     
     
       14. The apparatus of  claim 9 , wherein the two or more signals are obtained from user data. 
     
     
       15. The apparatus of  claim 9 , wherein the correlation is obtained by integrating a difference of the two or more signals over a period of time. 
     
     
       16. A method comprising:
 reading three signals from two or more tracks of a disk drive recording medium using three read transducers co-located on a slider; 
 determining a correlation between two of the three signals, the correlation being based on a difference between the two signals over a period of time; and 
 aligning the slider to at least one of the two or more tracks in response to the correlation. 
 
     
     
       17. The method of  claim 16 , wherein the two signals correspond to first and second read transducers located on either side of a center read transducer that produces a third of the three signals, and wherein aligning the slider comprises aligning the center transducer to the at least one track. 
     
     
       18. The method of  claim 17 , further comprising measuring an amplitude of the third signal, wherein aligning of the slider is further based on the amplitude. 
     
     
       19. The method of  claim 17 , further comprising determining a second correlation between the third signal with one or both of the two signals, wherein aligning of the slider is further based on the second correlation. 
     
     
       20. The method of  claim 16 , wherein the three signals are obtained from user data.